Coupling compounds for color forming development



Patented Apr. 18,1939

ING v Wilhelm Schneider and Hans Loleit, Dessau, Germany, asaignor' toAsia Ansco Corporation, Binghamton, N. Y., a corporation of New York NoDrawing. 'Applicafion June 28, 1938, Serial No. 216,293. In Germany July30, 1937 claims. (on. 95-88) The present invention relates to couplingcompounds for color forming development.

Color photographic pictures have been produced with the aid of colordeveloping dyestufl. components having active methylene groups which inthe development of a latent silver image by me'ans of a developercontaining a free amino-group.

produce a colored compound in the place of the silver image. Suchdyestuii components are, for example, derivatives of aceto-acetic acidesters,

or pyrazolone, of malonic acid esters, of cyanoacetophenone, ofcumaranone and ofhydrowthionaphthehe. I

It is an object of the present invention to provide an improvement in thprocess of producing photographic color pictures by color formingdevelopment.

A further object of the invention resides in the provision of a new andimproved class of dyestufi components, color formers or couplingcompounds.

Still another object of the invention is the proa the new class of colorformers.

A further object is to provide a photographic emulsion for color formingdevelopment having incorporated compounds from the new class of colorformers being fast to diffusion with respect to the silver halideemulsions.

Further objects of the invention will appear from the detailedspecification following hereinafter.

We-have found that an improvement in the process of producingphotographic color picturesby color forming development may be obtainedby employing as the color forming compounds capable of forming adyestuii with the oxidation product of an amino developer a pyridinederivative of the following general formula:

in which R stands for alkyl, aryl and aralkyl; X is a suitable inorganicacid radical, for example Cl,

55 and its derivatives, for example picoline, 3-aminopyridine ordipyridine. As ketones there may be used, for example,chloroacetophenone, bromacetophenone, monochloracetone,symmetricaldichloracetone, bromacetonaphthone, para-phenylbromacetophenone,para-phenylc fi p 5 none and diphenylene:para-para'-dichloromethylketone. The reaction of the methyl ketones and pyridine derivatives isexothermic. The opera tion of forming the compound may proceed in thepresence or absence of a solvent. Suitable so1- m vents are, forexample, benzene or ether. By

- double decomposition there may be obtained from the aforesaid halogenderivatives chlorates, sulfates, or the like.

The new dyestufi components may be added to 15 the developer or to theemulsion. In the development with a para-dialkylaminoaniline, yellowdyestuff pictures are produced.

when. these dyestufi coupling components are mixed in the photographiclayer they should be made ,fast to difiusion in the medium oi the layerby introduction of groups, which owing their chemical structure arecapable of imparting to the dyestufi components fastncss to diffusionwhile retaining their solubility in water. groups are, for instance,substantive groups as described in U. S. patent application Ser. No.72,718 filed April 4, 1936, radicals of highly polymeric carboxylicacids as describedinU. S. patent application Ser. No. 90,726 filed July15, 1936, 30 aliphatic radicals consisting of an extended saturated orunsaturated carbon chain as described in U. S. patent applicationSer.No. 94,340 filed August 5, 1936, said carbon chains preferablycontaining radicals which impart to the finished comthe layers or fromone layer to the other, such as 40 for instance polypeptide radicals (U.S. patent application Ser. No. 158,860 filed'August 13, 1937),

radicals of carbohydrates (U. S. patent application Ser. No. 159,518filed August 17, 1937), radicalsof natural resins (U. S. patentapplication Ser. No. 164,499 filed September 18, 1937), sterol radicals(U. S. patent application Ser. No. 166,832 filed Octoberl, 1937).Furthermore there may be used compounds in which the radical ofithedyestuff component itself recurs periodically (U. S. 5 3 patentapplication Ser. No. 171,701 filed October 29, 1937). Furthermoreradicals may be introduced into the molecule of the dyestufl com-'ponents which make the latter fast to diflusion, which radicals consistof hydroaromatic and Such ' chloride of the formula hydro-heterocyclicresidues, then further menthane radicals (U; S. patent application Ser.No. 176,058 filed November 23, 1937).

These groups may be introduced either directly into the ketone, as forexample into the diphenylacetyl chloride, into the pyridine nucleus orat any other position in the molecule, for example into the benzenenucleus of the bromacetophenone and indeed either directly or by meansof an amino-, hydroxyl-, or carboxyl group in the form of an acid amideor an ester.

The dyestuif components may be used in the production of both singlelayer materials and multi-layer materials, and in the latter case thelayers may be arranged on one or both sides of a support. Alternativelya mixture of emulsion particles containing different dyestufl componentsmay be applied to the support.

In the exposed silver halide emulsion the pic.-

ture may be produced by simple color forming development or by reversaldevelopment as described in U. S. patent applications Ser. No.

148,731 filed June 17, 1937, and Ser. No. 100,319 flled September 11,1936.

. The above described coupling compounds have an improved reactivity andform the desired dyestufls more easily than the hitherto known. colorformers, since the reactive methylene group appears to be activated bythe vicinal pyridine nucleus.

The following examples illustrate the invention:

Example 1.-An exposed silver halide emulsion layer is developed with adeveloper of the following composition:

(a) Para-dimethylaminoaniline ....grams 1 Anhydrous sodium carbonate..do 15 Sodium sulflte do Water cc 250 Potassium bromide "grams" 1 (b)Phenacylpicolinium chloride do 1. 8

Methanol cc.. 10

when the silver has been dissolved away a yellow dyestufl picture isobtained.

Example 2.An exposed silver halide emulsion layer is developed with adeveloper of the .following composition:

Ayellow dyestufl picture is obtained; Example 3.--3 grams ofdiphenylacylpyridinlum I 000g Ol are dissolved in 25 cc. of methanol endcc. of water, and the solution is added to 400 cc. of a gelatineemulsion of 5 percent strength, and the latter iscast to form a layer.By developing the exposed layer with dimethyl-aminoaniline there isobtained a yellow picture.

What we claim is:

1. In a process of producing photographic color pictures by colorforming development, the improvement which comprises employing as the.color forming compound capable of forming a dyestuff with the oxidationproduct of an aro-' matic amino developer, a pyridine derivative of thefollowing general formula improvement which comprises employing as "acolor forming developer a composition of matter comprising an aqueoussolution of an alkali, an

aromatic amino developing agent and a pyridine derivative of thefollowing general formula cl n-cocfil x in which R is a member of thegroup consisting of aikyl, aryl, and aralkyl, and X is an anion.

3. In a process of producing photographic color pictures by colorforming development, the

' improvement which comprises employing as a light-sensitive element aphotographic silver halide emulsion containing as the color formingcompound capable of forming a dyestufl with the oxidation product of anaromatic amino developer, a pyridine derivative of the following generalformula in which R is a member 01' the group consisting of alkyl, aryl,and aralkyl, and X is an anion, said pyridine derivative containing inits molecule a radical, which imparts thereto fastness to diffusion withrespect to the binding agent of the emulsion,'while retainingitssolubility in aqueous liquids.

4. Silver halide emulsion for color photography capable ofbeingdeveloped in color by means of an aromatic amino develop'r, saidsilver halii'le emulsion containing a pyridine derivative of thefollowing general formula inwhichRisamembei-ofthegroupconsisting ofalkyL-aryl, and aralkyl, and x is an anion;

*5. A color-forming developer comprising an aqueoussolution of an alhli.an aromatic amino developlng agent, and a pyridine derivative of inwhich R is a. member of the group eonsisfln:

the following general formula or alkyl, ml, and aralkyi, and x is ananion.

'wnnmm scmmmm. i we 1.0mm

